In a typical arthroscopic surgical procedure, fluid is pumped into a surgical field to create a positive pressure in a joint to provide space to perform the procedure and to reduce bleeding by creating a tamponade effect. Fluid is pumped into and out of the joint to remove debris and blood from the surgical site. A video sensing device typically provides images of the surgical site. A surgeon manually controls the inflow and outflow of fluid from the surgical site to prevent debris, blood or other particulates from degrading the image that is necessary to perform the procedure. This manual task can be difficult and lead to additional time for conducting a surgery and potentially compromise the surgery if the images are not acceptable.
Prior art U.S. Patent Pub. No. 2008/0243054 A1 discloses a known arrangement, as shown in prior art FIG. 1, for detecting and distinguishing blood and debris disposed within a shoulder joint during an arthroscopic procedure. The pressure in the shoulder joint, and the liquid flow from an irrigation system, is controlled to attempt to provide good viewing with the arthroscope by keeping video camera images free from blood and debris.
In prior art FIG. 1, the arrangement includes an operating control device 17 and a saline bag 10 connected to a liquid inflow pump 2 that pressurizes feed tubing 13. The arrangement includes a pressure sensor 5 joined to the feed tubing 13. The feed tubing 13 connects to an arthroscope 14 that includes a video camera 22. A shaver 15 connects to an outflow tubing 16 that is in fluid communication with an outflow pump 3. During flow, the pressure drops all the way from the inflow liquid pump 2 to the outflow pump 3. In prior art FIG. 1, a video signal processor 23 is shown adjacent the operating control device 17.
In prior art FIG. 1, the detection of hemoglobin is obtained by use of light reflected from the hemoglobin in blood disposed in the joint 1. The light reflected is that which is radiated by a light source (not illustrated) known in the art of endoscopy. The light is introduced in a designated channel in the arthroscope 14 that is placed in the shoulder. The reflection of white light is detected by the video camera 22, which is fitted on the arthroscope 14. The video signal that is output from the video camera 22 is provided to a video signal processor 23.
The video signal is composed of separate red, blue and green video signal components that, in combination, compose the video color information. The video signal from the camera 22 is fed to the signal processor 23 that divides every video line signal into 0.64 microsecond time slots. This arrangement corresponds to 100 time slots for every video signal line, where a picture frame is made up of 625 lines (PAL). The signal levels of red, blue and green are nearly the same for the images common in the view field of the arthroscope, meaning that it is generally ranging from white to black. If the signal level of red is >20% of either the blue or green during a time slot, a score of one is registered in a first frame memory in the signal processor 23. If the whole image is red, 62,500 score points would be registered. Every picture frame has its own score. The first frame memory in the signal processor 23 has a rolling register function that has the capacity of scoring points from 10 frames. The frame memory is updated as every frame is completed and delivered by the camera. At every new frame, the score value of the oldest frame is discarded. A score sum for the ten frames is calculated every time a new frame is delivered by the camera, thus introducing an averaging function.
If, during a period of 10 frames, the score sum is >30,000, blood is considered present, and if the score sum is >70,000, much blood is considered present.
If the score sum is >30,000, the video signal processor 23 will signal to the operating control device 17 which will react by increasing the flow of the aspiration pump to a higher level to rinse the shoulder. This higher level is preselected in the menu of the pump system, and is in this case 300 ml/min. If the score sum is >70,000, the flow will increase to 450 ml/min. When the blood detection determines that the increased flow has rinsed the shoulder as the signal level has returned to a low level, the aspiration pump will return to the intrinsic flow of 150 ml/min after a timeout of 30 seconds. Also, to stop bleeding of a ruptured blood vessel in the shoulder joint 1, the pressure in the joint is increased by a pressure control for the same time that flow is elevated. This pressure increase is predetermined in menu settings of the pump, and is in this example 40 mm Hg. Also other picture analysis techniques as known in the art could be used.
To detect debris, the signal processor 23 divides every video frame into 128×128 pixel elements. Every such pixel has a signal level that corresponds to the whiteness of the object that is visualized by the camera. This whiteness is nearly the same from video image frame to video image frame. The signal processor stores a value from 0 to 15 as this intensity value of the video signal of each pixel in a second frame memory. The pixel values are stored in a matrix fashion. For each video image frame 25 consecutive frame matrixes are stored. The second memory in the signal processor has a rolling register function that rolls the 25 frames in a first in-first out fashion. The second memory is updated as every video image frame is completed and delivered by the camera. As a new frame is developed by the camera, the oldest frame is discarded. A variation in the pattern in the second stored matrix is detected by the signal processing unit. This variation is identified as pixel intensities that are recognized as moving from one adjacent pixel to another in an identifiable fashion. As every pixel has a location in the matrix that corresponds to the physical image, a movement of intensity in the matrix location from image frame to image frame is a movement in relation to the surrounding, of a single object, in this case debris that float in the shoulder joint. Movement can be in any direction in the matrix. If 10 such movements are detected during one frame, a first score value is incremented by one in a memory cell representing a first score value. This score value is incremented for each detection, and is decremented down to 0 for every frame there is no such detection. If there are over 500 detections in one frame, the camera is moved, and no score values are given. Also, other picture analysis techniques as known in the art could be used.
Every second a frame matrix is stored in a third frame memory. This memory also has a rolling register function that rolls the 25 frames in a first in-first out fashion. If predominant consistently low signal levels are occurring in the third frame memory, dark areas are identified. If these dark areas are elevated to a consistent signal >25% level over a time of 5 seconds, homogeneous debris is identified as being present in the shoulder joint. Such occurrence increases the value of a second score value by 10. If there is no such occurrence, this second score value will be decremented by 10 down to 0.
If either the first or second score values are >50, debris is considered present, and the video signal processor 23 will signal to the operating control device 17 which will react by increasing the flow of the aspiration pump to a higher level to rinse the shoulder. This higher level is preselected in the menu of the pump system, and is in this case 300 ml/min. When the debris detection determines that the increased flow has rinsed the shoulder as the score value has returned to <50, the aspiration pump will return to the intrinsic flow of 150 m./min after a timeout of 5 seconds, and both score values are reset.
The system described above, however, is limited to an operating control device 17 for a pump that only controls liquid inflow for the arthroscope 14 and liquid outflow from a separate shaver 15. In this system, there is no control of any functions other than the liquid inflow pump 2 and liquid outflow pump 3. Further, the prior art system is limited to processing red, blue and green video signal components. Finally, the FIG. 1 system is limited to controlling flow pressure/inflow and outflow rates in order to obtain a desired video image.